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Ren Y, Cao X, Wu P, Li L. Experimental insights into the formation of secondary minerals in acid mine drainage-polluted karst rivers and their effects on element migration. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:160076. [PMID: 36356774 DOI: 10.1016/j.scitotenv.2022.160076] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/02/2022] [Accepted: 11/05/2022] [Indexed: 06/16/2023]
Abstract
Acid mine drainage (AMD) threatens the water quality and safety of karst river water (KRW), and the formation of secondary iron or aluminum-bearing minerals during the mixing of AMD with KRW plays a crucial role in the migration of elements. However, the variations in the mineralogical, morphological and elemental compositions of secondary minerals and their influences on the migration of elements during AMD-KRW mixing have not been systematically studied. In this study, we mixed different proportions of AMD and KRW in a laboratory experiment to simulate seasonal hydrological conditions in a river to understand the major and trace elemental distributions in the mixed water and in precipitates and we discuss the formation process for the secondary minerals. The results showed that AMD can lead to a decrease in pH and DO and an increase in heavy metals and rare earth elements (REEs) in KRW. With the biological or chemical oxidation of Fe2+, Fe3+ combines with SO42- to form schwertmannite or hydrolyzes to form Fe(OH)3(s) and FeOOH(s), accompanied by the formation of amorphous Al hydroxide, resulting in a decrease in pH and an increase in Eh. Schwertmannite had strong adsorption and coprecipitation effects on Mn, Cr, Cu and As, so the adsorption and coprecipitation effects of schwertmannite on REEs were inhibited, while the migration of REEs were mainly affected by Al hydroxides. Therefore, after the AMD mixes with KRW, it not only causes severe water and sediment pollution but also adsorbs and enriches high concentrations of heavy metals in the secondary minerals formed during the mixing process, creating a major ecological hazard that requires further attention.
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Affiliation(s)
- Yeye Ren
- College of Resources and Environmental Engineering, Guizhou University, Guiyang 500025, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guiyang 500025, China
| | - Xingxing Cao
- College of Resources and Environmental Engineering, Guizhou University, Guiyang 500025, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guiyang 500025, China.
| | - Pan Wu
- College of Resources and Environmental Engineering, Guizhou University, Guiyang 500025, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guiyang 500025, China
| | - Linwei Li
- College of Resources and Environmental Engineering, Guizhou University, Guiyang 500025, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guiyang 500025, China
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Gou D, Huang K, Liu Y, Shi H, Wu Z. Investigation of Spatial Orientation and Kinetic Energy of Reactive Site Collision between Benzyl Chloride and Piperidine: Novel Insight into the Microwave Nonthermal Effect. J Phys Chem A 2022; 126:2690-2705. [PMID: 35447029 DOI: 10.1021/acs.jpca.2c01487] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Microwave nonthermal effect in chemical reactions is still an uncertain problem. In this work, we have studied the spatial orientation and kinetic energy of reactive site collision between benzyl chloride and piperidine molecules in substitution reaction under microwave irradiation using the molecular dynamics simulation. Our results showed that microwave polarization can change the spatial orientation of reactive site collision. Collision probability between the Cl atom of the C-Cl group of benzyl chloride and the H atom of the N-H group of piperidine increased by up to 33.5% at an effective spatial solid angle (θ, φ) of (100∼110°, 170∼190°) under microwave irradiation. Also, collision probability between the C atom of the C-Cl group of benzyl chloride and the N atom of the N-H group of piperidine also increased by up to 25.6% at an effective spatial solid angle (θ, φ) of (85∼95°, 170∼190°). Moreover, the kinetic energy of collision under microwave irradiation was also changed, that is, for the collision between the Cl atom of the C-Cl group and the H atom of the N-H group, the fraction of high-energy collision greater than 6.39 × 10-19 J increased by 45.9 times under microwave irradiation, and for the collision between the C atom of the C-Cl group and the N atom of the N-H group, the fraction of high-energy collision greater than 6.39 × 10-19 J also increased by 29.2 times. Through simulation, the reaction rate increased by 34.4∼50.3 times under microwave irradiation, which is close to the experimental increase of 46.3 times. In the end, spatial orientation and kinetic energy of molecular collision changed by microwave polarization are summarized as the microwave postpolarization effect. This effect provides a new insight into the physical mechanism of the microwave nonthermal effect.
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Affiliation(s)
- Dezhi Gou
- College of Electronics and Information Engineering, Sichuan University, Chengdu 610065, China
| | - Kama Huang
- College of Electronics and Information Engineering, Sichuan University, Chengdu 610065, China
| | - Ying Liu
- College of Electronics and Information Engineering, Sichuan University, Chengdu 610065, China
| | - Hongxiao Shi
- College of Electronics and Information Engineering, Sichuan University, Chengdu 610065, China
| | - Zhiyan Wu
- College of Electronic and Electrical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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Zhang W, Zhang W, Wang S, Liu J, Li Y, Zhuo Y, Xu L, Zhao Y. Band application of flue gas desulfurization gypsum improves sodic soil amelioration. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 298:113535. [PMID: 34391105 DOI: 10.1016/j.jenvman.2021.113535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Blending flue gas desulfurization (FGD) gypsum with surface sodic soil is a universally recognized method for the rapid amelioration of sodic soils; however, little information is available on whether other application methods (band application) will reclaim sodic soil. Three FGD gypsum application methods (single-band, dual-band and blend applications) and a control treatment (non-FGD gypsum) were carried out using sodic soil in soil bins to investigate the effects of the application method on the wetting front, major cations in the leachate during the process of water infiltration and soluble and exchangeable cations in the soil profile after infiltration. The results showed that the wetting fronts in the band treatments were denser in the horizontal direction than in the vertical direction, but the blend and control treatments only had vertical migration. The main channel of the stream in the band treatment was concentrated below the application site of FGD gypsum. The orders of desalting capacity were blend treatment, dual-band treatment and single-band treatment for the same volume of outlet water. There was no water outflow in the control treatment even after 115 days of leaching. The dual-band treatment significantly decreased the soil sodicity of the 0-40 cm soil profile, while the single-band treatment only effectively reclaimed (horizontally) half of the soil. In the blend treatment, the exchangeable sodium percentages were 21.3 % and 34.7 % at depths of 30-35 cm and 35-40 cm, respectively, and were close to zero at a depth of 0-30 cm. Compared with blend treatment, band application could be a better way to reclaim sodic soil with FGD gypsum due to its advantages of long-term and efficient amelioration with low consumption.
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Affiliation(s)
- Wenchao Zhang
- Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China; Beijing Engineering Research Centre for Ecological Restoration and Carbon Fixation of Saline-Alkaline and Desert Land, Beijing, 100084, China; Shanxi Research Institute for Clean Energy of Tsinghua University, Taiyuan, 030032, China
| | - Wenxin Zhang
- Shanxi Research Institute for Clean Energy of Tsinghua University, Taiyuan, 030032, China
| | - Shujuan Wang
- Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China; Beijing Engineering Research Centre for Ecological Restoration and Carbon Fixation of Saline-Alkaline and Desert Land, Beijing, 100084, China; Shanxi Research Institute for Clean Energy of Tsinghua University, Taiyuan, 030032, China
| | - Jia Liu
- Beijing Engineering Research Centre for Ecological Restoration and Carbon Fixation of Saline-Alkaline and Desert Land, Beijing, 100084, China; Tsinghua Agriculture Co., Ltd., Beijing, 100084, China
| | - Yan Li
- Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China; Beijing Engineering Research Centre for Ecological Restoration and Carbon Fixation of Saline-Alkaline and Desert Land, Beijing, 100084, China; Shanxi Research Institute for Clean Energy of Tsinghua University, Taiyuan, 030032, China
| | - Yuqun Zhuo
- Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China; Beijing Engineering Research Centre for Ecological Restoration and Carbon Fixation of Saline-Alkaline and Desert Land, Beijing, 100084, China; Shanxi Research Institute for Clean Energy of Tsinghua University, Taiyuan, 030032, China
| | - Lizhen Xu
- Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China; Beijing Engineering Research Centre for Ecological Restoration and Carbon Fixation of Saline-Alkaline and Desert Land, Beijing, 100084, China; Shanxi Research Institute for Clean Energy of Tsinghua University, Taiyuan, 030032, China
| | - Yonggan Zhao
- Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China; Beijing Engineering Research Centre for Ecological Restoration and Carbon Fixation of Saline-Alkaline and Desert Land, Beijing, 100084, China; Shanxi Research Institute for Clean Energy of Tsinghua University, Taiyuan, 030032, China.
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